SYRIA – After nearly two years of fighting, Syria’s vaunted war machine is showing serious cracks as emboldened rebels snap up more bases and airfields and force army units to retrench behind defensive lines in major cities, Western officials and military analysts say.

Bolstered by a steady flow of arms from foreign backers, opposition forces have scored a series of tactical victories in the Damascus suburbs in recent days and are advancing steadily toward the city’s airport, adding to what some analysts view as a sense of momentum that has been building since late summer.

Powerful antitank and antiaircraft weapons have helped level what was once a lopsided contest, the officials say, so much so that army commanders have been unable or unwilling to challenge rebel assaults on large military bases on the capital’s outskirts.

“The regime isn’t intervening to defend its positions,” said Jeffrey White, a former Middle East military analyst with the Pentagon’s Defense Intelligence Agency. “And when it does try to counterattack, it often fails.”

Extremist groups among the Syrian opposition are responsible for some of the gains. Rebel commanders and outside analysts say the groups have grown more powerful in recent months because of funding and weapons from wealthy Arab donors in the Persian Gulf region as well as Syrian businessmen outside the country.

One Islamist militia with suspected ties to al-Qaeda has seized two government military bases in the past two weeks. (read more)